As compared to the solar calendar, the dates of Ramadan vary, moving backwards about ten days each year as it is a moving holiday depending on the moon. Ramadan was the month in which the first verses of the Qur'an were said to be revealed to the Islamic Prophet Muhammad.

It is the Islamic month of fasting, in which participating Muslims refrain from eating, drinking, that is in excess or ill-natured; from dawn until sunset. Fasting is meant to teach the Muslim patience, modesty and spirituality. Ramadan is a time for Muslims to fast for the sake of God (Arabic: الله, trans: Allah) and to offer more prayer than usual. During Ramadan, Muslims ask forgiveness for past sins, pray for guidance and help in refraining from everyday evils, and try to purify themselves through self-restraint and good deeds.

Origins of Ramadan

The name "Ramadan" had been the name of the ninth month in Arabian culture long before the arrival of Islam; the word itself derived from an Arabic root rmḍ, as in words like "ramiḍa" or "ar-ramaḍ" denoting intense heat, scorched ground and shortness of rations. In the Qu'ran, God proclaims that "fasting has been written down (as obligatory) upon you, as it was upon those before you". According to the earliest hadith, this refers to the Jewish practice of fasting on Yom Kippur.

Sometimes referred to as "the night of decree or measures", Laylat al-Qadr is considered the most holy night of the year, as it is the night in which the Qur'an was revealed to Muhammad. Muslims believe it to have occurred on an odd-numbered night during the last 10 days of Ramadan, either the night of the 21st, 23rd, 25th, 27th or 29th (in Sunni thought) or the 19th, 21st or 23rd (in Shi'a thought). Ramadan ends with Eid ul-Fitr on the 1 of Shawwal, with much celebration and feasting. During the month following Ramadan, called Shawwal, Muslims are encouraged to fast for a further six days, known as as-Sitta al-Bīḍ, or "the white six." When fasting is over, Muslims go to mosques in formal clothes to pray the first Eid prayer. They give out presents to the young ones and greet their friends and families. They then thank God for what He has given them.

The most prominent event of this month is fasting. Every day during the month of Ramadan, Muslims around the world get up before dawn to eat Sahur or Sehri or Sahari (meaning "something we eat at Sahar"), then they perform the fajr (or Sobh) prayer. They have to stop eating and drinking before the call for prayer starts until the fourth prayer of the day, Maghrib. Muslims break their fast at Maghrib (at sunset) prayer time with a meal called Iftar. Muslims may continue to eat and drink after the sun has set until the next morning's fajr prayer call. Then the process starts all over.

Muslims should start observing the fasting ritual upon reaching the age of puberty, so long as they are healthy, sane and have no disabilities or illnesses. The elderly, the chronically ill, and the mentally ill are exempt from fasting, although the first two groups must endeavor to feed the poor in place of their missed fasting. Also exempt are pregnant women, women during the period of their menstruation, and women nursing their newborns. A difference of opinion exists among Islamic scholars as to whether this last group must make up the days they miss at a later date, or feed poor people as a recompense for days missed. While fasting is not considered compulsory in childhood, many children endeavour to complete as many fasts as possible as practice for later life. Lastly, those traveling (musaafir) are exempt, but must make up the days they miss. More specifically, Twelver Shī‘ah define those who travel more than 40 mi (64 km) in a day as exempt.

The elderly or those who suffer from a disability or disease and have no prospect of getting better in the future can pay the cost of Iftar for a person who cannot afford it, or else they can host such a person in their house and have him eat with them after sunset as a way of repaying for the days they could not fast.

A person who is observing Ramadan might break the fast accidentally, due to having forgotten it. In such an instance, one might spit out the food being eaten or cease the forbidden activity, immediately upon remembering the fast. This can usually happen in the early days of Ramadan because that person might have not yet been acclimated into fasting from dawn till dusk.

When Ramadan came to overshadow Ashura in importance, it took on some characteristics of the latter. According to a well-known hadith, the person who observes Ramadan properly will have all their past sins forgiven. According to another, "When Ramadan arrives, Heaven's gates are opened, Hell's gates are closed, Satan is chained up and jinns are also locked up" and who ever dies will enter paradise.

There are exceptions in certain Muslim communities that deny practising fasting in Ramadan such as Alevi people in Turkey.

In addition to fasting, Muslims are encouraged to read the entire Qur'an. Some Muslims perform the recitation of the entire Qur'an by means of special prayers, called Tarawih, which are held in the mosques every night of the month, during which a whole section of the Qur'an (Juz', which is 1/30 of the Qur'an) is recited. Therefore the entire Qur'an would be completed at the end of the month.

Ramadan is also a time when Muslims are to slow down from worldly affairs and focus on self-reformation, spiritual cleansing and enlightenment; this is to establish a link between themselves and God through prayer, supplication, charity, good deeds, kindness and helping others. Since it is a festival of giving and sharing, Muslims prepare special foods and buy gifts for their family and friends and for giving to the poor and needy who cannot afford it; this can involve buying new clothes, shoes and other items of need. There is also a social aspect involving the preparing of special foods and inviting people for Iftar.

In many Muslim and non-Muslim countries with large Muslim populations, markets close down in the evening to enable people to perform prayers and consume the Iftar meal – these markets then re-open and stay open for a good part of the night. Muslims can be seen shopping, eating, spending time with their friends and family during the evening hours.

The Islamic holiday of Eid ul-Fitr (Arabic: عيد الفطر) marks the end of the fasting period of Ramadan and the first day of the following month, after another new moon has been sighted. The Eid falls after 29 or 30 days of fasting, per the lunar sighting. Eid ul-Fitr means the Festival of Breaking the Fast; a special celebration is made. Food is donated to the poor (Zakat al-fitr); everyone puts on their best, usually new, clothes; and communal prayers are held in the early morning, followed by feasting and visiting relatives and friends. The prayer is two Raka'ahs only, and it is optional (mustahabb) prayer as opposed to the compulsory five daily prayers. Muslims are expected to do this as an act of worship, and to thank God.

Hilāl (the crescent) is typically a day (or more) after the astronomical new moon. Since the new moon indicates the beginning of the new month, Muslims can usually safely estimate the beginning of Ramadan.

The month of Ramadan is that in which the Quran was revealed, a guidance to men and clear proofs of the guidance and the Criterion. So whoever of you is present in the month, he shall fast therein, and whoever is sick or on a journey, (he shall fast) a (like) number of other days. Allah desires ease for you, and He desires not hardship for you, and (He desires) that you should complete the number and that you should exalt the greatness of Allah for having guided you and that you may give thanks.

--Qur'an 2:185

There are disagreements each year however on when Ramadan starts. This stems from Saudi traditions to sight the moon with the naked eye and as such there are differences for countries on opposite sides of the globe. More recently however, more Muslims are leaning towards using astronomical calculations to avoid this confusion.

In some Muslim countries, failing to fast or the open flouting of such behavior during Ramadan is considered a crime and is prosecuted as such. For instance, in Algeria, in October 2008 the court of Biskra condemned six people to four years in prison and heavy fines.

In Kuwait, according to law number 44 of 1968 the penalty is a fine of no more than 100 Kuwaiti dinars, or jail for no more than one month, or both penalties, for those seen eating, drinking or smoking during Ramadan daytime. In UAE, eating or drinking during the daytime of Ramadan is considered a minor offence and would be punished by up to 240 hours of community service.

Ramadan is a time of reflecting and worshiping God. Muslims are expected to put more effort into following the teachings of Islam and to avoid obscene and irreligious sights and sounds. Sexual activities during fasting hours are also forbidden. Purity of both thoughts and actions is important. The fast is intended to be an exacting act of deep personal worship in which Muslims seek a raised awareness of closeness to God.

The act of fasting is said to redirect the heart away from worldly activities, its purpose being to cleanse the inner soul and free it from harm. It also allows Muslims to practice self-discipline, self-control, sacrifice, and empathy for those who are less fortunate; thus encouraging actions of generosity and charity (Zakat).

Eid al-Fitr, often abbreviated to Eid, marks the end of Ramadan, the Islamic holy month of fasting (sawm). Eid is an Arabic word meaning "festivity", while Fiṭr means "to break fast". It is celebrated on the first day of Shawwal.